Bifold doors are the most commonly used door for closets in
residential construction. There are many styles of bifold doors
availabe from six-panel,louvred,and mirrored just to name a
few. Bifold doors also allow one to practically see the whole
contents of a closet when fully open.

The rough opening for a bifold door will depend on how the
opening will be finished. There are two choices on how this is
done. One rough opening involves wrapping the opening with
drywall. The other choice is framing the rough opening for a
door jamb and casing, sometimes called a cased opening.

The rough opening for a drywall wrapped opening must allow
for the thickness of the drywall. This is usually 1/2" thick
drywall and what we will use for our example. In our example we
are installing a 4' bifold door. The finished opening for these
doors is four feet. Since we are wrapping our opening with 1/2"
drywall, we need to add 1" to our finish opening size. Our
rough opening width will be 4'1" or 49 inches. For our rough
opening height, we want 82 inches to the bottom of our header.
This allows for the 80 inches the doors and track need, a 1" to
1 1/2 inch space under the door and 1/2 inch drywall on the
bottom side of the header. Our rough opening for a 4"0" set of
bifold doors will be 49" x 82".

The rough opening for a bifold cased opening will be framed
wider. The opening is framed like a rough opening for an
interior door. We are allowing for framing additional space for
a door jamb. The door jambs are 3/4 of an inch thick. This is a
total of 1 1/2 inches we must add to our four foot bifold door
example. We must also add 1/2 inch of space for shimming. This
gives us a total width of 50 inches. Our total height for these
doors is the doors and track plus 2 inches or 82 inches. The
rough opening for a 4'0" cased opening would be 50" x 82".

These are pretty straight forward examples of rough openings
for bifold doors. One must also consider floor finishes when
figuring the rough opening. Depending on the thickness of the
floor the use of underlayment the rough opening may need to be
framed taller. Keep this in mind when you are framing your next
rough opening for bifold doors.